Pipe forming machine



Aug. 20, m'.

H. L. MOOR PIPE FORMING MACHINE Filed May 51, 1943' 2 Sheets-Sheet 1 INVENTOR.' #FQMA/v Moo/Q.

Au., w 1946.

H. L. MOR

PIP-E FORMING MACHINE Filed May 3l, 1945 2 Sheets-Sheet 2 .INVENTOR. #EQ/MN L Moog. BY l l* Patented Aug. 20, 1946 40ans PIPE FORMING MACHINE Herman L. Moor, Olive Township, St. Joseph County, Ind.

Application May 31, 1943, Serial No. 489,109

This invention relates to a pipe forming machine.

The primary object of the invention is to provide a machine for simultaneously making and laying in a trench a continuous and jointless pipe formed of concrete or other plastic material.

A further object is to provide a machine of this character with means for incorporating reinforcing material within a pipe as the same is formed.

A further object is to provide a machine of to and supported by the rear end of walls II at this character for compacting backll around a form in advance of the pipe-making and layingN operation, whereby said compacted backll constitutes the outer form for the pipe.

A further object is to provide a machine of this character with means for vibrating the plastic material while the same passes from feed means to molding forms thereof.

A further object is to provide a device of this character having an elongated exible inner form trailing therebehind to provide an interior support for the fresh-laid pipe during the period the same is setting to shape.

A further object is to provide a machine of this character which is self-propelling.

A further object is to provide a machine of this character with a rotating and vibrating cylinder mounting a screw to feed plastic to and compact it in an annular mold cavity, said cylinder constituting part of an inner pipe mold.

Other objects will be apparent from the drawings, description and appended claims.

In the drawings:

Fig. 1 is a top plan view of the machine with parts shown in longitudinal transverse section taken on line I-I of Fig. 2.

Fig. 2 is a longitudinal vertical sectional view taken on line 2-2 of Fig. 1.

Fig. 3 is a vertical transverse sectional View taken on line 3-3 of Fig. 2.

Fig. 4 is a Vertical transverse sectional view taken on line 4 4 of Fig. 1.

Fig. 5 is a vertical transverse sectional view taken on line 5-5 of Fig. 2.

Fig. 6 is a vertical transverse sectional View taken on line 6 6 0f Fig. 2.

Fig. 7 is a side view of the vibrating inner cylinder of the machine.

Referring to the drawings, which illustrate the preferred embodiment of the invention, the numeral II] designates the frame or body of the machine. Frame I is formed of rigid metal plate material and comprises vertical side walls II, an arcuate bottom I2, and an arcuate front I3, said bottom and 'front merging in a curved portion I4.

21 Claims. (Cl. .Z5-3.2)

rearwardly from the frame.

An larcuate longitudinal wall I concentricwith bottom I2 extends from a point intermediate the ends of the frame to the rear of the frame and merges with a cylindrical portion I6 projecting The outer diameter of portion I6 conforms -with the outer dia-meter of the pipe to be formed. A vertical chute or passage I1 projects upwardly from wall .I5 and communicates with a hopper I8 which is secured its upper end.

Two or more cross bars I9 are secured to and extend transversely between the walls II adjacent the front thereof and an internal combustion engine or other drive means is mounted thereon by any suitable mounting members 2|. Drive shaft 22 of the engine projects rearwardly therefrom and is journaled at its end in a bearing 23 carried by a cross bar 24 extending transversely between and secured to the side walls I I.

A pinion 25 is keyed to shaft 22 and meshes with a gear v25 therebelow keyed to a shaft 21. The shaft 21 is journaled in a bearing 28 supported by a cross bar 29 extending between and secured to sides II. A second lbearing 30 mounted on a bracket arm 3I supported at the front end of wall I5 also journals shaft 21. A bevelled pinion 32 is mounted on the rear end of shaft 21 vand meshes with a bevel gear 33 keyed to a transverse. shaft 3d. The ends of shaft 34 are mounted in openings formed in side walls I-.I and spanned .by plates 35 secured to the outer faces of said walls. Shaft 34 is journaled in bearings 36 supported by vertical bracket arms 31, Fig. 3, projecting upwardly from wall I5 and by longitudinal bracket arms 38 projecting forwardly from chute .I1. Adjacent .the opposite ends thereof, shaft `34 has circular .cams 39 mounted eccentrically thereon and -keyed thereto and encircled by rings mounted on the forward ends of a pair of bars 4I extending longitudinally at opposite sides of chute I1. Bars 4I mount a transverse ramming plate 42 at their rear ends and adjacent and rearwardly of the rear ends of side walls II. The plate `42 is of a width slightly less than the width .of frame Ill, .and has a concave arcuate lower 4edge ,43 whose radius is slightly greater than the radius of the outer. periphery of frame cylinder I6 upon which the lower central portion of said plate 42 bears in spaced relation to the rear end of said cylinder. y

A wideannular bearing 44 is mounted at the forward end of the annular space dened by frame bottom I2 and wall I5, said bearing preferably comprising Aan outer raceway -45 and an inner raceway 46, each having two or more spaced registering circumferential grooves receiving hard metal bearing balls 41, and end retainer rings 48 suitably constructed to seal oil therein and exclude plastic. A cylinder 49 is journaled in bearing 44 adjacent its front end.

Cylinder 49 is best illustrated in Figs. 2 and '1, and its outer diameter is equal to the inner diameter of the pipe' to be formed. The cylinder is elongated to project rearwardly from the cylinder' I6 at 59 and to project forwardly of wall l5 at 5|. A helical external feed screw 52 is carried by the central portion of cylinder 49, extending from bearing 44 to a ,point substantially coincident with the rear end of frame cylinder I6. The

screw 52 is of a diameter less than the inner diameter of cylinder I6. Two or more spaced longitudinal ribs 53 are secured within`cylinderv I6, said ribs being of a thickness to be engaged by screw 52 to form supports for the cylinder rearwardly of bearing 44. -The rear end of cylinderA 49 is provided with aclosure plate or spider 54 having Ya central aperture 55 therein. A closure plate 56 is removably mounted on the front end of cylinder 49 and has a central bea-ring 51. A disc 58 Ais fixedly mounted within the cylinder intermediate the ends thereof and has a. central bearing 59. A shaft 6,6 having a central bore 6I therethrough is journaled in bearings 51 and 59, and projects forwardly `from the cylinder. An unbalanced arm 62 is xedly secured on shaft 69 adjacent disc 58. A pair of abutment rings 63 are-secured to shaft 60 onropposite sides of bearing 51 to prevent relative endwise movement of the shaftand cylinder. The portion of cylinder between disc 58 and closure plate 56 may contain cooling fluid, such as oil.

A pulley 6 4 is mounted on engine shaft 22 forwardly of pinion 25, and a pulley 65 is mounted on the forwardly projecting end of shaft 60. A `belt 66, preferably a V-belt, is trained around said pulleys to rotate shaft Vlill and unbalanced ann 62 at comparatively high speed, thereby causing said shaft and the cylinder to vibrate.

The forward projecting end portion I of cylinder 49 mounts an `annular sprocket 61, and a sprocket 68 is mounted on shaft 21 intermediate bearings 28 and 39. A chain 59 is trained around said sprocketsto rotate cylinder 49. It will be noted that the cylinder 49 is rotated at a low speed compared with the rate of rotation of shaft 4lill, by virtue of the speed reduction effected through gears 25 and 26 and through sprockets 61 and 68.

An elongated flexible inner pipe form trails behind cylinder 49. As herey illustrated, this forni is made up of a plurality of articulated annular non-collapsible sections or elements -10 each of the same outer diameter as portion 50 of cylinder 49. Each element 10 hasv a reduced diameter portion 1I projecting from the front end thereof and tting within the rear end of the preceding element or of the cylinder 49 with a small clearance The rear edge of each element and the shoulder between the same and portionll at the -front thereof, are preferably :rounded or tapered at 12. The construction and intertting relation of elements is such as to permit a limited amount of angular displacement of adjoining elements 10 to'permit the same to follow a bend in a pipe. The elements 19 are interconnected by a, cable 13 passing therethrough. The front end of cable 13 extends through opening 55 in rear cylinder wall 54 and fixedly mounts a fitting 14 bearing against .said cylinder wal1. The rear` end pf cable 13 Cil extends into the rearmost element 10 and xedly mounts a fitting 15 having a cup-shaped or annular retainer 116 against which the rear end of a tensioned coil spring 11 encircling said cable bears. A disc 18 having a small central aperture 'i9 nts within the rearmost element 10 and bears marginally against the internal shoulder between element 19 and reduced diameter collar 1| of said element. Spring 11 presses against the outer outer face of disc 18, and cable 13 passes freely through aperture 19. Any selected number of .l elements 10 may be interconnected in this manported in a socket 8l carried by the lower portion of the front of said frame, and being positioned by retainers S2 above said socket. The uppermost retainer may include a hitch ring 83. Mast 89 preferably extends to a considerable height, and mounts brackets 84 projecting laterally and oppositely therefrom adjacent its upper end. Each bracket 84 journals a pulley 85. A pair of opposite laterally projecting brackets 86 is secured to mast intermediate the height thereof. Each bracket 86 mounts a winch 81. A guy cable B8 is wound on each winch, extending upwardly around a pulley and then extends laterally to an anchor spaced from the trench 89 in which the machine operates. Mast 80 is preferably of such height and the guy anchors are preferably so spaced from the trench that workmen and vehicles may pass thereunder without interference. Whiletwo guys have been illustrated and may be adequate to support the machine in vertical position in the trench, four may be used if desired by providing the necessary number of pulleys and Winches therefor.4

An. elongated bent tube 90 having a vertical portion secured to the` front of the frame at 9| and a rearwardly longitudinally extending lower portion supported by a bracket 92 is mounted within the machine frame with its rear portion terminating adjacent to and in axial alignment with shaft 60. Suitable means (not shown) may feed reinforcing wire 93 (Fig. 5) into said tube to be guided therethrough and into bore 6I of shaftI 60. A second bent tube 94 has its ends secured by an Lshaped bracket 95 xedly secured within the cylinder 49 rearwardly of disc 58, whereby one end thereof is axially aligned with bore 6l to guide wire 93 from the shaft bore to and through a hole 96 in the cylinder. As here illustrated, hole 96 extends through one of the convolutions of screw 52 at a point rearwardly of ribs 53 and adjacent the rear end of cylinder i6, whereby said wire is coiled as cylinder 49 is rotated. f

One or more additional tubes or guides 91 'may be mounted within the frame at the front thereof, supportedby brackets, as brackets 9i and 92, for passage of longitudinal reinforcing rod stock therethrough by any suitable means (not shown). Frame lll and wall I5 may have longitudinally spaced openings 98 and 99 therein through which such rod stock may be'pas'sed. The rearmost openings will preferably be positioned in advance of the front ends of ribs 53, Scthat said rod may pass therebetween to be guided longitudinally thereby.

The operation of the device is as follows: The machine is lowered into trench 89 and may be pulled along therein immediately behind a trench digging machine by4 any suitable means (not shown) which pulls a draw member .connected t0.

the machine at 83, or the machine may be permitted to propel itself as hereinafter described. The guy cables 98 are connected to hold mast 89 and the machine frame in vertical position; the reinforcing wires 93 and the longitudinal reinforcing rods are threaded or guided to proper feeding position in the machine; and hopper I8 is filled with the concrete or other mix; and the machine is ready for operation. Best results are obtained by using a concrete mix containing a minimum amount of water, and the mix may also be treated to impart quick-setting properties thereto. i

Upon operation of the engine 20, three operations occur, apart from the feed of the reinforcing wire and rods, namely, reciprocation of ram arms 4I and ram plate 42 by cams 39, rotation of cylinder 49 by chain 69, and rotation of shaft 99 and unbalanced arm by belt 65. Backfill I is continuously emptied into the trench 89, and is compacted by the ram plate 42 whose stroke terminates forwardly of the rear end of frame cylinder I6. Hence cylinder I9 constitutes an outer form around which the backll is compacted, so that the machine forms a circular earth tunnel therebehind. Also, it will be apparent that if the backfill material is emptied into the trench continuously, the action of the reciprocating ram plate 42 pressing thereagainst will serve to prop-e1 the machine forwardly in the trench at a rate proportional to the rate at .which the backiill material is fed. rIhis action assumes, of course, that the backll material is of a consistency to permit compactingl thereof, since it will be apparent that the backll must be finely compacted to form an abutment against which the pushing action may be exertedand also to maintain its shape after the frame cylinder passes therefrom.

The rotation of cylinder 49 serves to rotate screw 52 to feed the plastic mix rearwardly for continuous discharge into the annular cavity between the inner form and the circular cavity in the compacted backll behind the cylinder I6. By properly correlating the rate of forward movement of the machine with the rate at which cylinder 49 is rotated, the mixis compacted in the annular receiving cavity therefor to insure uniformity and solidity of the pipe IUI being formed. Rotation of the cylinder 49 also serves to wind reinforcing wire 93 into helical form concentric with and properly positioned in the pipe wall intermediate the inner andr outer peripheries thereof.

The cylinder is vibrated by the comparatively high speed rotation of shaft 69 and unbalanced arm 62 therein, and thus the plastic mix is vibrated as it is kpropelled in the cylinder I6 by screw 52. This also assists in the compacting and solidifying of the mix. Note that the journaling of the cylinder 49 at its forward end.- only provides a cylinder mounting facilitating vibration. At the same time, the provision of the longitudinal ribs 53 in the frame forms a 'support for the free or unjournaled end of the cylinder to limit the extent or amplitude of the vibrations and to limit the stresses applied to bearing 44 by the vibration. The high speed rotation of shaft 6l] and the incident vibration generates heat, and consequently the filling of the forward end of the cylinder with a liquid, such as oil, serves as a heat transfer means to hold the heat at'bearing surfaces, etc., within safe limits and to uniformly transmit the heat to the cylinder walls to heat the mix. f

A concrete mix requires a certain minimum time forsetting thereof, during which time theV mix must be confined within aform,VVV This is accor'n'plishe'd` in theinstant device by thetrailing flexible' inner' form. The length of this form which is required will depend upon various factors, including the rate at which the machine advances, the setting properties of the mix, i, e., the percentage of water contained in a concrete mix, etc., .and the quantity of reinforcing metal employed. Thus the length of the trailing form used with concrete pipe may vary from a minimum of forty or fifty feet to two hundred feet or more. Note that the rotation of cylinder 49 by which the trailing form is drawn may impart a limited rotation to at least some of the elements of the trailing form, and such rotation in conjunction with the forward movement of the trailing form serves to smooth and finish the mix at the interior of the pipe as the mix is setting up, thus forming a smooth solid inner peripheral pipe surface which is a distinct advantage.

It will be apparent that the guy cables must be advanced from time to time as the machine advances, and this renders the provision of four such cables, together with automatically adjustable Winches 81, an advantage inasmuch as the operation of the machine may then be continuous since the machine would not then have to, be stopped for guy cable manipulation. It will be understood, however, that guy cables have been shown and described as illustrative only of one convenient means for positioning the machine, and that other positioningmeans may be utilized if desired.

From the above it will be apparent that the machine possesses the following distinct advantages, among others: automatic operation; manual labor or attendance is held at a low point; the machine is capable of self-propulsion; all attendants work at ground level; a strong compact jointless pipe is produced; the pipe is formed in the position at which it is to remain in use, thereby minimizing the problem of stresses incident to settling of surrounding earth; and the speed and low cost of the finished, backfllled pipe as compared to the cost of a conventional pipe line which includes the multiple factors of manufacturing cost, transportation, handling, joining and back-filling, etc.

i Another feature of the machine is that it is not adversely affected if small quantities of water are present in the trench, since the mix is fed into the receiving cavity therefor between the inner form and the compacted contoured earth back-fill under pressure sufiicient to force the water ahead of the rear end of frame cylinder I6, and thus prevent adverse effect thereof upon the newly poured mix.

1. A machine kfor forming a pipe in a trench, comprising a frame adapted for movement Ain said trench and having a lower cylindrical portion, a reduced diameter cylindrical rotatable member concentric with said frame cylinder and cooperating therewith to deiine an annular chamber, and means for feeding plastic material to and rearwardly through said chamberv into said trench, said cylindrical member including an elongated portion formed `of relatively rotatable articulated sections normally in frictional end engagement adjacent their circumference projecting rearwardly from said frame to continuously interiorly support said mix While the latter sets in said trench.

2. Afmachine for forming a pipe in latrench,

comprising a frame adapted to be advanced in said trench and having a lower longitudinal passage, an inner formrotatable within-said'passage and cooperating therewith to denne a tubular chamber, -means for feeding plastic material to and rearwardly through said chamber into said trench, and an elongatednon-collapsible flexible trailing member in torque transmitting end engagement with said rotatable form and projecting rearwardly from said frame to interiorly support-said mixrwhile the same sets in said trench, said trailing member including a plurality ofarticulated relatively rotatable, cylindrical por;-v tions in torque transmitting end'engagement.

k3. A machine for forming a pipe in a trench, comprising a frame adaptedto be advanced .in said trench and having a lower longitudinal passage, an inner form rotatable within said-passage and cooperating therewith to define a tubular chamber, means for feeding plastic material to and rearwardly through said chamber into said trench, and an elongated flexible trailing form of substantially uniform cross .section including a plurality of relatively rotatable articulated rigid units connected to and in rotation transmitting engagement with the rear end of said inner form. Y

4. A machine for forming a pipe in a trench, comprising a frame adapted to be advanced in said trench, and having a lower longitudinal passage, an' inner form within said passage and cooperating therewith to dene a tubular chamber, means for feeding plastic material to and rearwardly through said chamber into said trench, and an elongated flexible trailing form of substantially uniform cross section in frictional end abutment withV said inner form and including a plurality of similar rigid tubular units each having a reduced portion fitting in frictional torquetransmitting relation to an adjacent unit and an elongated flexible draft member passing through said units with its opposite ends connected to said inner form and to said rearmost unit.

5. A machine for forming a pipe in a trench, comprising a frame adapted to be advanced in said trench and having a lower longitudinal passage, a cylindrical form journaled in said passage and cooperating therewith to dene a tubular chamber, a feed screw in said chamber carform in frictional end engagement with and drawn by said first form to continuously interiorly support said plastic material in saidtrench as it sets said last named form including-a plurality of relatively rotatable cylindrical sections in frictional torque transmitting end to end engagement.

6. A machine for formi-ngrapiperinra trench; comprising a frame adapted for movement through said trenchand' having 'a lrearwardly projecting tubular portion, an inner form within said tubular portion' dening'a tubular chamber in said frame, said inner form including a uniform rearwardly trailing portion, a ram reciprocable longitudinally of said frame for packlng earth around said tubularframe portion, and means for feeding plastic material to and through said chamber for discharge between said trailing form portion and said packed earth rearwardly of said frame.

7. A machine for forming pipe'in `alt-trench,

tudinally shiftable ram for packing earth around said tubularl frame portion.

8. A machine for forming a pipe in atrench, comprising a frame having a rearwardly projecting tubular portion, aninner form in said tubular portionV cooperating therewith to define a tubular chamber, means for feeding plastic material to and rearwardly' through-said chamber, a transverse substantially vertical ram, and means for longitudinally reciprocating said ram to pack earth around said tubular frame portion and thereby advance said frame.

9. A machine for forming a pipe in a trench, comprising a frame having a rearwardly projecting tubular portion, an inner form in said tubular portion cooperating therewith to dene a tubular chamber and including a portion projecting rearwardly from said frame, Ya transverse substantially Vertical ram plate, a transverse cam shaft journaled in said frame, means for rotating said shaft, longitudinal bars so arranged as to be shifted by said shaft and connected to said ram plate, said ram plate reciprocating longitudinally on said tubular frame portion to compact backiill therearound, and means for feeding plastic material through said chamber and compacting it around said inner form rearwardly of said frame.

l0. In a machine for forming a pipe in a trench, a frame, a hopper carried by said frame, a longitudinal tubular portion at the bottom of said frame projecting rearwardly therefrom and communicating with said hopper, a substantially vertical transverse ram plate bearing on said tubular portion rearwardly of said hopper, means carried by said frame for longitudinally reciprocating said ram plate to compact backll deposited around said tubular portion, said plate and means advancing said frame as backfill is deposited therebehind, and an inner pipe form in Asaid tubular portion and projecting rearwardly therefrom for shaping the interior of a pipe formed from material discharged from said hopper.

1l. A machine for forming a pipe in a trench comprising a frameadapted to be advanced in said trench, an outer form carried by the bottom of said frame, a cylindrical inner form rotatably mounted within said outer form to denne a tubularchamber therein, a'helical feed member xed to and encircling a portion Yof said inner form, means for feeding plastic material to said chamber, a shaft iournaled longitudinally in said inner form, an unbalanced weight carried by said shaft within said form, means for rotating said inner form, and means for rotating said shaft and weight at higher speed than the speed of rotation of said inner form to vibrate said inner form 12, A machine for forming a pipe in a trench,

comprising a frame having an outer form iixedly carried by and projecting rearwardly from the lower portion of said frame, a transverse substantiallyY vertical lram plate above said outer form, means for longitudinally reciprocating said ram plate'to compact backflll around said outer form, an inner form mounted within said outer form to denne a tubular chamber therein, means for feeding plastic material to and through said chamber, and means for vibrating said inner form. y Y

13. A machine for forming a pipe in a trench, comprising a frame having an outer form Xedly carried by and projecting rearwardly from the lower portion of said frame, longitudinally reciprocable ram means for compacting backll around said outer form, an inner form journaled within said outer form to define a tubular chamber therein, a feed screw xed to and encircling said inner form, means for supplying plastic material to said chamber, means for rotating said inner form, and means for vibrating said inner form.

14. A machine for forming a pipe in a trench, comprising a frame having an outer form xedly carried by and projecting rearwardly from the lower portion of said frame, longitudinally reciprocable ram means for compacting backll around said outer form, an inner form journaled within said outer form to define a tubular chamber therein, a feed screw xed to :and encircling said inner form, means for supplying plastic material to said chamber, means for rotating said inner form, and means for vibrating said inner form, said inner form including an elongated flexible, non-collapsible portion projecting rearwardly of said outer form.

15. A machine for forming pipe in a trench, comprising a frame adapted to be advanced in said trench and having an outer form in the lower portion thereof, an inner form rotatable in and projecting from said outer form and cooperating therewith to define a tubular chamber, means for feeding plastic material to and rearwardly through said chamber, said inner form having an opening therein intermediate the length thereof, means for feeding a flexible reinforcing member to and through said opening including an open ended passage extending axially of said inner form and curved at one end for registration with said opening, and means for rotating said inner` form.

16. A machine for forming pipe in a trench, comprising a frame adapted to be advanced in said trench and having an outer form fixed in the lower portion thereof, a tubular inner form journaled at its forward end portion within said outer form and cooperating therewith to dene a tubular chamber, means for feeding plastic material to :andrearwardly through said chamber, a longitudinal open ended hollow shaft journaled in said inner form, an unbalanced weight fixed on said shaft, said inner form having an opening therein rearwardly of said shaft, means for feeding a flexible reinforcing member through said hollow shaft and thence laterally through said opening, means for rotating said inner form, and means for rotating said shaft.

17. A machine for forming a pipe in a trench, comprising a frame adapted to traverse said trench and having a longitudinal passage at its bottom dened in part by a rearwardly projecting tubular portion, a rotatable cylindrical form within said passage and cooperating therewith to form a tubular chamber, means for rotating said form, an articulated cylindrical form trailing and providing a continuation of said cylindrical form, means reciprocating substantially horizontally for compacting earth around said rearwardly projecting frame portion as said frame advances, a feed screw in said chamber carried by said rotatable form, means for feeding plastic material to said chamber, and means for transversely vibrating said rotatable form.

18. A machine for forming pipe in a trench, comprising a frame adapted to traverse a trench and having an elongated longitudinal passage deiined in part by a tubular portion projecting rearwardly from the lower portion of said frame, means reciprocating substantially horizontally for compacting earth around said passage as said frame advances, means for feeding plastic material to and rearwardly through said passage, an inner pipe form within said passage and including a uniform portion projecting rearwardly from said passage, said plastic material being discharged and shaped between said inner forms and said compacted earth rearwardly of said frame.

19. A machine for forming a pipe in a trench, comprising a frame adapted to traverse said trench and having a rearwardly projecting form at the lower portion thereof, longitudinally reciprocable means for compacting backflled earth around said form, an inner form within said outer form and projecting rearwardly therefrom, means for discharging plastic material around said inner form rearwardly of said frame, and means for maintaining said frame upright in said trench.

20. A machine for forming a pipe in a trench, comprising a frame adapted to traverse said trench and having a rearwardly projecting form at the lower portion thereof, longitudinally reciprocable means for compacting backlled earth around said form, an inner form within said outer form and projecting rearwardly therefrom, means for discharging plastic material around said inner form rearwardly of said frame, a vertical mast carried by said frame, and guy cables carried by said mast and anchored at points spaced from said trench for maintaining said frame and mast upright as said frame advances.

21. A machine for forming pipe in a trench, comprising a frame having an outer form in the lower portion thereof, an inner form rotatable in and projecting from said outer form and cooperating therewith to define a tubular chamber, means for feeding plastic material to and rearwardly through said chamber, means for feeding a reinforcing member into said chamber including a passage extending axially of said inner form with its forward end open to receive said member and terminating in a lateral portion opening through said inner form, and means for rotating said inner form.

HERMAN L. MOOR. 

